The present invention relates to a apparatus for the melt-spinning of a plurality of strand-like filaments in a yarn forming operation.
For the melt-spinning of synthetic fibers, a melted polymer material is extruded to form a plurality of strand-like filaments. For this, it is necessary that the polymer melt be pressed through nozzle holes. The extrusion, which is also called spinning out, is done by a spinneret which comprises on its underside a plurality of nozzle holes. In practice, several spinnerets of this type are used simultaneously alongside one another in order to extrude several fiber bundles in parallel to one another. For this, the spinnerets are held in a nozzle holder.
In operation, it is necessary that the spinnerets be removed and given maintenance at regular intervals. The removal of the spinnerets is laborious and causes unavoidable downtimes which lead to a loss of production. There is thus the desire to fashion the design of the spinnerets, as well as the connection of the spinnerets to a nozzle holder, in such a way that they can be removed in as simple a manner as possible. Here the leak-tightness of the components must be ensured at all times during operation since the polymer melt is conducted and extended under a high melt pressure.
Apparatus are known from DE 199 35 982 A1, DE 42 36 570 A1, and the corresponding U.S. Pat. Nos. 6,716,016 and 5,387,097, respectively in which the spinnerets or spinneret blocks are secured in place in the nozzle holder in order to make the interface between a melt outlet of the nozzle holder and a melt inlet of the spinneret pressure-tight. For this, a cylindrical seal is secured in place between the melt outlet and the melt inlet. However, apparatus of this type have the basic disadvantage that during operation a deformation of the sealing ring occurs so that a securing in place between the sealing ring and the nozzle holder hinders the loosening of the spinneret. In addition to this, the spinneret must be secured in place against the nozzle holder with high securing forces in order to ensure the sealing function at the interface between the melt outlet and the melt inlet so that correspondingly high de-securing forces are required to loosen the spinneret.
DE 16 60 375 and corresponding U.S. Pat. No. 3,500,499 discloses an apparatus in which the housing and the nozzle plate of the spinneret are held in a receptacle of the nozzle holder in such a manner that they can move relative to one another and in such a manner that the connection between the melt outlet of the nozzle holder and the melt inlet of the spinneret is sealed automatically. However, the movable arrangement of the individual parts of the spinneret has the great disadvantage that the spinneret is not held in the nozzle holder in such a manner that it can be removed as a structural unit. Furthermore, the concept requires an additional sealing point within the spinneret.
It is accordingly an object of the invention to provide a melt spinning apparatus of the type stated initially in such a manner that, on the one hand, the spinneret is held in the nozzle holder in such a manner that it can be loosened easily and, on the other hand, high pressure forces for sealing can be produced between the spinneret and the nozzle holder.